Eustress: Acute stress that disappears quickly and is not repeated chronically at a level the individual cannot respond to adequately (recover). Eustress is known as 'good stress' and appropriate physical exercise is an example which tends to improve health and fitness. Eustress tends to be associated with psychological and physiological arousal rather than anxiety. Any stress that is chronic has the potential to become distress. See also the GUS Stress Category.